An opium den is read as the pull of escape and forgetting — a place where time and worry seem to dissolve. Tradition sees it as a question about what you are trying to numb, and about habit and control.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.